What air tube do I get to put on my rim?

[mef1975]

It's a Crystalyte HS-3540 for a 26" tire, purchased at ebikedeal.com.

The rim measures 1.5" wide, with a diameter that appears to be 22.5".

I got these tubes for it...
http://www.ebay.com/itm/2-pk-Bicycle-Tubes-Self-Sealing-26-X-2-00-2-40-w-Sealant-Inside-48mm-Presta-/301181495168?pt=US_Tubes&hash=item461fd0e780

...and this tire, which I've yet to receive...
http://www.amazon.com/Schwinn-Cruiser-Kevlar-Black-2-12-Inch/dp/B007XZ2OJ0/ref=sr_1_1?s=sporting-goods&ie=UTF8&qid=1418075796&sr=1-1&keywords=schwinn+tire+26+2.125

, but the tube doesn't fit snug, at all, even after filling with air, it just comes right off, several inches of slack, in fact. What size tube should've I gotten, 24"?

 

[dogman dan]

Tube should not come off once you have a tire around it. I think you got the right size tube.

It's possible your tire doesn't fit well though, I've had some that needed careful inflation so the bead doesn't pop off one side. I definitely prefer a tire that needs tools to install, rather than one so loose you can pop it on with bare hands.

 

[marty]

Put a little air in the tube. Put tube inside tire. Mount tire on rim. Careful to not pinch tube with sharp tools if prying tire onto rim. Fingers are best tool.
Metal and plastic tire levers

 

[Voltron]

Re. Several inches of slack..are you just putting the tube around the rim with no tire to check the fit? If so it won't fit tight...but if it is actually those tubes pictured, just by eyeball they seem skinnier than 2.0-2.4 size, and presta valve might not work with your pump?

 

[Voltron]

And usually you want to mount one side of the tire, then put in the tube (with a little air in it ), then push the other bead into place with your thumbs..

 

[amberwolf]

, but the tube doesn't fit snug, at all, even after filling with air, it just comes right off, several inches of slack, in fact. What size tube should've I gotten, 24"?

Tubes aren't designed to fit snug on the rim without a tire to constrain them. Until you receive and put your tire on on there, the tube is not going to fit right.